Britain and France talked about a "union" in the 1950s, even discussing the possibility of the Queen becoming the French head of state, it was reported today.

On September 10 1956, Guy Mollet, the then French prime minister, came to London to discuss the possibility of a merger between the two countries with his British counterpart, Sir Anthony Eden, according to declassified papers from the National Archives, uncovered by the BBC.

A British cabinet paper from the period reads: "When the French prime minister, Monsieur Mollet, was recently in London, he raised with the prime minister the possibility of a union between the United Kingdom and France."